Isentropic primitive equations for the moist troposphere

Despite the knowledge that the potential temperature of an air parcel has a dependence on its water vapour content, potential temperature is often still calculated as if the parcel were dry, assuming that this moisture dependence is negligible. We show that such a dry potential temperature approxima...

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Main Authors: Lee, Shao-Yi, Koh, Tieh-Yong
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2014
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Online Access:https://hdl.handle.net/10356/103655
http://hdl.handle.net/10220/19294
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1036552020-03-07T12:45:26Z Isentropic primitive equations for the moist troposphere Lee, Shao-Yi Koh, Tieh-Yong School of Physical and Mathematical Sciences Earth Observatory of Singapore DRNTU::Science::Physics::Meteorology and climatology Despite the knowledge that the potential temperature of an air parcel has a dependence on its water vapour content, potential temperature is often still calculated as if the parcel were dry, assuming that this moisture dependence is negligible. We show that such a dry potential temperature approximation is not suitable for tropical regions. Moisture gradient terms are seen in the isentropic primitive equations when Exner and Montgomery functions are generalised with moist specific heat capacities, forming a contribution to the horizontal momentum tendency comparable to that by the Montgomery function. This reflects how local horizontal gradients in potential temperature created by inhomogeneous water vapour distribution are relatively significant compared to gradients created by inhomogeneous temperature, in a large-scale background of weak horizontal temperature gradient. In such an environment, water plays an active role in tropical atmospheric dynamics without the uptake or release of latent heat during phase changes. Hence, we suggest that the tropical troposphere is a place where the atmosphere can behave dynamically as a binary-component fluid at local and regional scales. 2014-05-02T08:56:22Z 2019-12-06T21:17:09Z 2014-05-02T08:56:22Z 2019-12-06T21:17:09Z 2013 2013 Journal Article Lee, S. Y., & Koh, T. Y. (2014). Isentropic primitive equations for the moist troposphere. Quarterly Journal of the Royal Meteorological Society, in press. 0035-9009 https://hdl.handle.net/10356/103655 http://hdl.handle.net/10220/19294 10.1002/qj.2312 en Quarterly journal of the royal meteorological society © 2013 Royal Meteorological Society. 7 p.
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic DRNTU::Science::Physics::Meteorology and climatology
spellingShingle DRNTU::Science::Physics::Meteorology and climatology
Lee, Shao-Yi
Koh, Tieh-Yong
Isentropic primitive equations for the moist troposphere
description Despite the knowledge that the potential temperature of an air parcel has a dependence on its water vapour content, potential temperature is often still calculated as if the parcel were dry, assuming that this moisture dependence is negligible. We show that such a dry potential temperature approximation is not suitable for tropical regions. Moisture gradient terms are seen in the isentropic primitive equations when Exner and Montgomery functions are generalised with moist specific heat capacities, forming a contribution to the horizontal momentum tendency comparable to that by the Montgomery function. This reflects how local horizontal gradients in potential temperature created by inhomogeneous water vapour distribution are relatively significant compared to gradients created by inhomogeneous temperature, in a large-scale background of weak horizontal temperature gradient. In such an environment, water plays an active role in tropical atmospheric dynamics without the uptake or release of latent heat during phase changes. Hence, we suggest that the tropical troposphere is a place where the atmosphere can behave dynamically as a binary-component fluid at local and regional scales.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Lee, Shao-Yi
Koh, Tieh-Yong
format Article
author Lee, Shao-Yi
Koh, Tieh-Yong
author_sort Lee, Shao-Yi
title Isentropic primitive equations for the moist troposphere
title_short Isentropic primitive equations for the moist troposphere
title_full Isentropic primitive equations for the moist troposphere
title_fullStr Isentropic primitive equations for the moist troposphere
title_full_unstemmed Isentropic primitive equations for the moist troposphere
title_sort isentropic primitive equations for the moist troposphere
publishDate 2014
url https://hdl.handle.net/10356/103655
http://hdl.handle.net/10220/19294
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